Variable-resistance device



Jan. 20, 1925- L. G. PACENT VARIABLE RESISTANCE DEVICE Filed sept 12' VENTO 684C211) BY @NQQ RNEYs Patented Jan. 20, 1925.

UNITED STATES PATENT OFFICE.

LOUIS G. PACENT, OF WINFIELD, NE! YORK, ASSIGNOR T PACENT ELECTRIC COM- PAN'Y, INQ, OF NEW YORK, N. Y" A CORPORATION OF NEW YORK.

VARIABLE-BESISTANCE DEVICE.

Application filed September 12, 1923.

To all whom it may concern Be it known that I, Louis G. Pacnxr. a citizen of the United States, residing at \Vinfield, in the county of Queens. State of New York, have invented certain new and useful Improvements in Variabledtesistance Devices; and I do hereby declare the follow: ing to be a full. clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains, to make and use the same.

This invention relates to variable electrical devices, and, more particularly, variable resistance devices including rheostats and otentiometers.

One object of the invention is to provide an improved device of the character referred to which can be operatively mounted on a panel (as in a radio receiving set) or '1' 20 on a board or table for experimental or temmounting or in changing from one type of mounting to another.

vAnother object is'to provide a rheostat or potentiometer of sturdy and reliable construction' in which the assembled elements form a self-contained unit which is adapted to be permanently adjusted at the factory,

requiring no further adjustment on the part of the user. .Consonant with the foregoing objects, a rheostat or potentiometer typifying the preferred embodiment of the invention comprises a base of insulating material on which is mounted an arcuate resistance element, an apertured metal bushing journaled in the base, and a contact arm secured to the bushing and adapted to be rotated therewith for wiping over the resistance element. The base is provided with screw holes for mount ing it on the back of a panel or the top of a table. A shaft for rotating the bushing, together with a contact arm of proper size to fit the aperture in the bushing, may be insorted from either end of the bushing. Thus, if the rheostat or potentiometer, as the case may be, is mounted on the back of a panel, the shaft may be inserted through an aperture provided in the panel into the bushing and there secured by a set screw or other suitable means. On the other hand, if the device is mounted on a table top or board, the shaft is inserted into the bushing from Serial No. 662,197.

the opposite end as compared with the case above referred to, in which it is mounted on the back of a panel. Shifting the operatin shaft from one position to another as above described is effected without disturbing the adjustment of the device-this being one of the important features of the invention.

Other novel features of the invention will be pointed out in the following detailed description and appended claims.

Referring to the accompanying drawing,

Fig. 1 shows a fragmentary portion of a panel with a potentiometer'inounted thereon;

Fig. 2 is a cross-sectional view of the panel and potentiometer taken along the line 2- 2 of Fig. 1; i

Fig. 3 is an elevational view of the potentiometer wth the panel sh'own in cross section;

Fig. 4 is a plan view of the potentiometer showing the contactarm;

Fig. 5 is a plan view corresponding with Fig. 4 but showing the operating shaft and knob adapted for mounting on 'atable top or board; 1 p 'i Fig. 6 is an elevational view showing the potentiometer mounted on a table top with the operating shaft inserted in the side opposite that in which it is shown inserted in Fig. 3; and

Fig. 7 is aperspective viewflof the resistance. element forming a partg f the potentiometer.

A cylindrical base 1 molded insulating material is formed with a peripheralshoulder 1 against whichtan a'rcuate' resistance element 2 is positioned. Resistance' element 2 comprises a strip. of fieiribleinsulating material 2 such as fibre or the like around. which is wound a large numberof tur'ns of resistance wire. 2". Three binding posts 3, t and 5 each comprising a round head ma chine screw 6, washer 7, lock nut 8 and slotted nut 9 are mounted on the base 1 and rigidly secured thereto. The two ends of the strip of insulating material 2" are each provided with an aperture for engaging screws 6 of binding posts 3 and 5 and the two ends of the resistance wire 2 are connected respectively to the binding posts 3 and 5.

The base 1 is provided with a central aperture 1 in which is journaled a metal bushing 10 having a hexagonal head 10" which is tapped to receive a small set screw 11. On

Fig. 2.

the reduced end portion of the bushing 9 there is assembled a dished spring washer 13 and a plain washer 12. The reduced end of bushing 10 is riveted over against the washer 12 as shownin Fig.2, whereby these parts are permanently secured together. The spring washer 13 is provided with an integral tail piece 13 which connects with binding post 4, as shown most clearly in A contact arm 14 adapted to efl'ect wiping engagement with the resistance wire 2 isiformed as shown in Fig. 4, to engage the hexagonal head 10 of the bushing 10. Contact arm 14 is thus seen to be rotatable 15 with the bushing 10 and is electrically connected through the medium of bushing 10 spring washer 13 and tail piece 113 with binding post 4. A shaft 15 having a flat side 15 milled thereon is adapted tofit the aperture in bushing .10. the flat side of the shaft being engageable by the end of set screw 11, whereby the shaft is adapted for rotating the hushingfi together witlrcontact arm 1,4. Shaft. 15 is preferably' provided with i a molded knob ,of insulating material 19.

\Vhen the potentiometer is mounted on a panel as shown in .Figs hl, 2, 3 and Lthe shaft 15 is inserted through the panel and into the a erture in bushing 9, as is'c'learly shown in ig. 2, andis secured in place by the .set screw .11. When'thus mounted the base 1 is secured to thepanel by means. of screws 16 which engage'nu-ts' 17,

When it is desired to mount the potentiometer on a table or board for experimental purposes, the.ni it s' 17 can beremovedand the device mounted as shown' in Fig fi by means of a pair of wood screws. In the latter instance the shaft is inserted from the opposite endby the.bushin g 9'as compared with .Fig. 2. It 'willlbc noted that shifting the shaft from one side to the other for the purpose of mountingfon a panel or table top i espect'ively involves onlyloos ening the set screw 11, removing and reinserting the shaft in the position desired, and again tightening the set screw. This does notlinvolve any dislocation of the contact arm or in anyway interfere with. its proper 'arm adjustment. This makes it possible to preperly' adjust the contact pressure of the 14 against the resistance wire'with the assurance that it will remain so adjusted throughout the normal life of the device.

A punched metal part 18,"shown most clearly in Figs. 4 and 5, is preferably, but not necessarily provided with which the contact arm 1-1 may be engaged when it is desired to entirely cut out the resistance between terminals 4 and If desired, an ad ditioual member similar to 18 may be mounted on binding post 3.

It is quite obvious that the device illustrated and describedcan be utilized as a rheostat, in which event one of the binding posts 3 5 would not be employed as a terminal.

I claim:

1. In a variable resistance device, a base adapted for mounting on a panel, 'a pair of spaced terminals mounted on saidbase, a resistance element comprising an arcuate strip of insulating material having a resist ance wire wound thereon. said element being mounted on said base and secured at'its ends b y said terminals, at least one of said terminals being electrically connected'to said wire; a rotatable contact arm for wiping over said iesi'sfianee' wire, a punched metal terminus secured'to one of said terminals and adapted to engage saidcOnt-actarm 'for cutting sa1d resi stancew1re'out of'circui't, and

LOUIS G. PACENT. 

